JPL podcast: IT Came From Vesta.

Transcript

Detective (aside): to anyone out there - in the time I have left,
I will try to tell you all I know about their arrival...

Sound effects: knocking

Detective: Mr. Patel - you there?

Sound effects: music

Detective (aside): their infiltration began - like so many others

Detective (aside): their trail of smoke and flame did not go unnoticed.
Two Australian station workers, heroes I call 'em, just going about
their buesiness, they saw 'em come down.

Detective (aside): the station workers did not know the import
of their detection, so nobody looked for nothing. It would be ten
years before anybody realized -

Sound effects: footsteps. Then knocking on door.

Raymond: Yes?

Sound effects: door opening

Detective: Dr. Raymond, Mr. Patel, there's Eucrites on planet Earth!

Sound effects: Fade in ominous music

Patel: Did you say Eucrites?

Detective: Yeah -- Eucrites!

Raymond: This may shock you, but there are Eucrites all are over
the planet.

Sound effects: fade up music

Agle: That version of "IT came from Vesta" is our salute
to science fiction. That being said, you may find the science reality
of meteorites - and Eucrite meteorites in particular - just as intriguing

Agle: I'm DC Agle of the Jet Propulsion Lab. And here to discuss
Eucrites and the mission that will explore them we have with us
today: NASA's Dawn Mission Project Manager Keyur Patel

Patel: hello

Agle: and Dawn's deputy principal investigator, Dr. Carol Raymond

Raymond: hello

Agle: First off - where did Eucrites come from?

Patel: Well, they come from Vesta. It's the second largest body
in the asteroid belt. It's a 330-mile-wide space rock, and it has
a 285-mile-wide crater on it.

Raymond: and that crater - that's the smoking gun

Agle: there are a lot of big craters out there in the solar system.
So what makes this one on Vesta so special?

Raymond: It's special because that's where the Eucrites came from.
Eucrites formed in the interior of Vesta as melted rock that rose
and flowed across the surface. And then they were expelled from
the surface during a huge cataclysmic collision that released more
energy than any weapon ever devised by man -- and that sent about
one percent of the volume of Vesta out into the asteroid belt.

Agle: So Eucrites are out there in the asteroid belt. How did they
get from there to Earth?

Patel: Well you have to thank massive Jupiter for that. There is
a gap in the asteroid belt where objects floating around can be
greatly affected by Jupiter's gravity.

Raymond: And then over time Jupiter's gravitational tugging sends
some of that material, those Eucrites, on a path that crosses the
Earth's orbit.

Agle: So we have a huge deep space blast millions maybe billions
of years on a multi-billion mile trip and then a plunge into earth's
atmosphere

Agle: that is a great story but how can we prove it?

Raymond: Well we have some evidence. We have a spectral signature
of Vesta - which is a specific unique chemical fingerprint - and
we also can analyze the Eucrites that fall to Earth, in laboratories,
and look at their chemical fingerprints. And what we find is that
the unique signature matches between Vesta and the Eucrites.

Agle: So that story about the Australians who saw the Eucrites fall,
that is actually true?

Raymond: Yes, to my knowledge the only identified case where somebody
has seen a eucrite falling to Earth.

Agle: Are the eucrite meteorites found only in Australia?

Raymond: No, they have been found in Antacrtica and Canada and
all over the planet.

Agle: The Eucrites came here. Are we ever going there?

Patel: Yes we are. We are going to do that with the Dawn mission
which was launched on Sept. 27, 2007. It's going to go to Vesta first.
It's going to arrive there in 2011. It's going to orbit for a few
months, leave Vesta and arrive at Ceres, the dwarf planet, in February
2015.

Agle: What kind of science will we do when we arrive at Vesta?

Raymond: We are bringing it some instruments. We are bringing it
some cameras to image the surface, a mapping spectrometer which
will give us a much more precise spectral match between the Eucrites
on Earth and the surface of Vesta. We are also using a gamma ray
and neutron detector to make an even more precise match of some
of the elements in the crust of Vesta with those samples that we
have on Earth.

Agle: I've got to ask - do you love this stuff?

Raymond: It's really cool that you can hold a piece of deep space
in your hand (while) standing on the earth, and then send a spacecraft
out to go to where it came from and study that.

Agle: That's it from NASA's Jet Propulsion Laboratory. For the
latest on Eucrites, Vesta and the entire dawn mission please visit
us on the web at: